\[ x^{2 c-2} y'(x)+(c-1) x^{2 c-3} y(x)+y^{(3)}(x)=0 \] ✓ Mathematica : cpu = 0.0368737 (sec), leaf count = 183
\[\left \{\left \{y(x)\to c_1 \, _1F_2\left (\frac {1}{2}-\frac {1}{2 c};1-\frac {1}{c},1-\frac {1}{2 c};-\frac {x^{2 c}}{4 c^2}\right )+4^{-1/c} c_3 c^{-2/c} \left (x^{2 c}\right )^{\frac {1}{c}} \, _1F_2\left (\frac {1}{2}+\frac {1}{2 c};1+\frac {1}{2 c},1+\frac {1}{c};-\frac {x^{2 c}}{4 c^2}\right )+2^{-1/c} c_2 c^{-1/c} \left (x^{2 c}\right )^{\left .\frac {1}{2}\right /c} \, _1F_2\left (\frac {1}{2};1-\frac {1}{2 c},1+\frac {1}{2 c};-\frac {x^{2 c}}{4 c^2}\right )\right \}\right \}\]
✓ Maple : cpu = 0.108 (sec), leaf count = 73
\[ \left \{ y \left ( x \right ) =x \left ( \left ( {{\sl Y}_{{\frac {1}{2\,c}}}\left ({\frac {{x}^{c}}{2\,c}}\right )} \right ) ^{2}{\it \_C2}+{{\sl Y}_{{\frac {1}{2\,c}}}\left ({\frac {{x}^{c}}{2\,c}}\right )}{{\sl J}_{{\frac {1}{2\,c}}}\left ({\frac {{x}^{c}}{2\,c}}\right )}{\it \_C3}+ \left ( {{\sl J}_{{\frac {1}{2\,c}}}\left ({\frac {{x}^{c}}{2\,c}}\right )} \right ) ^{2}{\it \_C1} \right ) \right \} \]